FIG. 6 is a diagram showing the basic principles of edge registration for sheets being fed into a device, as known in the prior art. A sheet S is sent through a path in a process direction indicated as P toward a marking device generally indicated as 10. At a short interval before the sheet is fed through marking device 10 to receive an image thereon, the sheet is caused to pass over, in one particular embodiment, an optical sensor 20, which functions to detect an edge of the sheet.
FIG. 5 is a plan view of a portion of prior art multi-row linear sensor 600, for example, as would be used in a digital copier. FIG. 5 shows a two-dimensional array of photosensors. An existing chip design, such as could include the portion shown for FIG. 5, has photosensors that are too large for precise detection of a sheet edge, for example, as discussed for FIG. 6. That is, the sensor configuration of FIG. 5 does not provide adequate resolution for edge detection operations.